In view of the high wear factors imposed upon rock crushing machinery, many proposals have been made in an attempt to increase the life of the rock engaging components of such rock crushers.
Traditionally operators of rock crushing machinery have sought to overcome the gradual loss of efficiency due to wear of the rock engaging components by hard face welding metal to the rock engaging components.
When such rock crushers are used for crushing wet and abrasive lime rock, heavy wear factors are imposed on the impact crusher hammers, which necessitates frequent hard face welding to the impact crusher hammers sometimes on a daily basis. In practice four to ten hours a day have been spent by welders endeavoring to maintain the efficiency of such rock crushing machinery. Not only is this welding process an extremely expensive operation, but this operation also involves considerable danger in that it is often necessary for the welder to work in a hostile environment and in cramped locations adjacent the impact crusher hammers.
In order to eliminate this costly and potentially dangerous problem, rock crushing machinery has been produced that enables the easy replacement of rock engaging components. A capping system to replace stock hammers has totally eliminated the need for hard face welding. Such caps for attachment to the hammer carrier are removably fastened to the hammer carrier, and when the caps become worn it is a relatively easy operation to remove the cap and replace the same with new caps.
U.S. Pat. No. 3,838,826 to J. M. Wallace, et al. assigned to Capeletti Brothers, Inc. teaches a rotor having diametrically-opposed hammer carriers. Each of the hammer carriers defines a plurality of dovetail undercut grooves disposed substantially tangentially relative the axis of rotation of the rotor. A plurality of hammer caps, each having a dovetail extension extending therefrom, are able to be slid tangentially relative the hammer carrier, such that the extension and groove cooperate to lock the hammer cap in position relative the hammer carrier. Fastening means are used to rigidly secure the hammer cap relative the hammer carrier.
While the proposal of Wallace, et al. greatly increased the speed with which a rotary crusher could be serviced, this proposal still left a need in the art of a hammer cap that could easily be reversed such that when wear occurred on one of the rock engaging faces of the cap, the cap could be reversed, and thus the considerable expense of replacing a set of hammer caps could be avoided, or at least halved.
The hammer assembly of the present invention overcomes the aforementioned inadequacies of the prior art devices by providing a reversible cap that can easily be oriented through 180.degree. to present a second hard face into a position for crushing material on rotation of the rotor. It is the primary object of the present invention to provide a rotary rock crusher that overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which significantly contributes to the reliability and the ease with which a hammer assembly for a rotary rock crusher may be serviced.
Another object of the invention is the provision of a reversible cap for fastening to the hammer member, such that the reversible cap may be oriented through 180.degree..
Another object of the invention is the provision of a hammer assembly which greatly reduces the cost of replacement of the material engaging caps.
Another object of the present invention is the provision of a reversible cap for a hammer assembly which avoids the time-consuming and dangerous operation of welding that has been employed to hard face impact crusher hammers.
Another object of the present invention is the provision of a reversible cap for a hammer assembly which is quick and simple to install.
A further object of the present invention is the provision of a reversible cap for a rotary material crusher which may be retrofitted to a plurality of conventional primary impacters.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Particularly with regard to the use of the invention disclosed herein, it should not be construed as being limited to hammer assemblies for the attachment to the rotor of a rotary material crusher, but should include reversible caps for application to any material crushing apparatus and the like.